Sometimes things are not what they seem. An Intel integrated circuit, sold by a local computer shop as a 400 MHz Pentium II, may have been a 333 MHz Pentium II when it left the Intel factory. A defense contractor who ordered a specially-tested $50 bolt for use in a demanding aerospace application may be supplied with an inferior 50 cent bolt instead. Many enterprises suffer by such fraudulent product substitution.
Considering more particularly the integrated circuit case, IC manufacturers rigorously test their chips to assure that published specifications are met under all expected operating conditions. A chip that meets specs when operated at 400 MHz commands a substantial price premium over a chip that meets specs only at 333 MHz.
Commonly, chips with lower speed ratings are produced on the same fabrication lines as chips with top speed ratings but, during post-fab testing, fail to meet the more demanding spec under some extreme of operating conditions (e.g. at stressful ambient conditions, marginal power supply potentials, etc.). Unscrupulous distributors, aware that such chips may meet the higher specs under most conditions, sometimes “push” the speed ratings and re-mark, e.g., a 333 MHz chip as the much more costly 400 MHz chip.
Accounts of such duplicity are common. The Jun. 5, 1998, Orange County Register reported on purchasers who were duped into buying 233 MHz Pentium II processors for $620 each (instead of their then-prevailing $198 price), thinking they were 300 or 350 MHz models. Three days later, an account of such deception appeared in Computer Dealer news, this time involving incidents in Germany. Soon thereafter, Hong Kong Customs officials seized HK$ 2.9 million of similarly re-labeled Pentium II processors. (South China Morning Post, Aug. 18, 1998.)
Large computer companies, wary of unscrupulous chip distributors, commonly perform their own quality assurance testing of incoming chips. This testing is complex, costly, and time-consuming, but is viewed as necessary in order to assure the quality of the computer company's products.
One solution to this problem is for the manufacturer to encode—at the conclusion of testing—the chip's speed in a write-once memory (e.g. fusible links) formed in the integrated circuitry. This data can then be read-out by a subsequent purchaser of the chip to determine the original manufacturer's intended speed rating. Such an arrangement is detailed in Intel's U.S. Pat. No. 5,734,274.
While this electrical-encoding approach obviates the need for the purchaser to perform its own lengthy quality assurance testing, other drawbacks persist. For example, the purchaser must still remove the chip connector from its static-protective packaging and mate it with the socket of a reader device in order to discern the encoded speed data. So doing exposes the chip to potential static damage, thus requiring that this procedure be performed in a highly controlled environment by skilled personnel. Moreover, this approach increases the semiconductor die size, and impacts the yield.
A related approach is to form several (e.g. eight) metal traces on or near the exterior of the integrated circuit package, and laser-cut selected traces to represent one of, e.g., 256 different product grades/configurations. Such an arrangement is detailed in Intel's U.S. Pat. No. 5,686,759.
While an improvement in some respects over the fusible link approach, this latter technique has drawbacks of its own. For example, the provision of the metal traces on or near the exterior of the package limits packaging options, and makes assembly of the package more complex. Moreover, fairly sophisticated inspection equipment must be used to discern these product markings.
Finally, both of the foregoing approaches are suitable only with integrated circuits and the like, and have no counterpart, e.g., for bolts, etc.
To mark articles other than circuitry, a variety of techniques can be used. Most commonly, alphanumeric symbols are printed or otherwise formed on articles, permitting identification by inspection. However, such markings can readily be altered (as demonstrated by the remarking of integrated circuits, discussed above).
If a product marking is to be made resistant to tampering, a first step is to hide its significance from potential tamperers. One way of doing this is to employ computer-readable indicia (such as bar-codes), instead of alphanumeric symbols.
While bar codes are less likely to invite tampering than alphanumeric symbols, they still stand out as product markings. Still better would be product markings that, altogether, escape recognition as such.
Various such techniques are known. For example, numerous patents teach the marking of paper currency, lottery tickets and the like, with magnetic particles, phosphorescent dyes, etc. Such marking permits the authenticity of the articles to be verified. But the “bandwidth” of such inconspicuous techniques is quite limited, commonly being restricted to a single valid/invalid determination. Moreover, most such techniques are ill-suited for after-the-fact application to an article. Instead, such markings must generally be implemented as part of the article's original formation
In accordance with a preferred embodiment of the present invention, the foregoing and other drawbacks of the prior art are overcome. In an illustrative embodiment, the ceramic or plastic housing of an integrated circuit is provided with a textured surface in which digital data is encoded. The texturing does not alert the public to the conveyance of data, yet tens- or hundreds- of bits of data can be conveyed. The textured surface can be “read” using a hand-held scanner, without exposing the integrated circuit to possible static damage. Chip speed, together with other encoded data (e.g. date of fabrication, place of fabrication, size of cache, etc.) can thereby be discerned. Inspection of chips can be performed quickly by less-skilled personnel, and without special environmental controls.
In some embodiments, the texturing is effected through tooling used to produce, or modify, the packaging. In others, the texturing is effected by a patterned layer of additional material applied to a smooth surface. In still other embodiments, the surface is not textured but instead is printed with a seemingly random pattern in which the digital information is encoded.
These techniques can be applied to any utilitarian object. Pharmaceuticals, compact disks, bolts and special hardware, automotive parts, and wristwatches, are just a few other examples.
The foregoing and other features and advantages of the present invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.